This charming film features the great Katherine Hepburn late in her career. She plays Miss Pudd, a junk dealer in a northern California town. Alby and Chris live in the same town. Alby lost his grandfather a year earlier. Alby's grandfather was quite a man in his day. He was a barnstormer, and used to sail a hot air balloon over carnivals and county fairs while performing feats of daring do. The boys have a plan to memorialize Alby's grandfather. On his birthday, they plan to launch his old hot air balloon. In order to do that they patronize Miss Pudd's junk yard. At first she's having none of it and tells them to leave, but when she finds out what they want to do, she's enchanted.
They become a team. Miss Pudd provides the boys with what they need to make the balloon work and the boys include her in their plans. One of the more delightful elements of the movie is the independence of the children. Parents are almost never seen. The film centers on the world of the kids. Below is Kate's monologue after the balloon runs away with them and she wonders if they'll ever get home.
This film is available on DVD (I rented it from Netflix), though very little video of it exists online. The above clip, uploaded by CardboardShoreline was all I could find aside from an interview with the prop master on the film, which is wonderful as well. It was also called The Great Balloon Adventure, as the poster above advertises it. The poster is available from MoviePosterShop.com. I think I was one of the few kids to see this on its first release. It was shown in the midwest briefly in '78, then released in New York in 1981 but pulled rather quickly.
Obscurity factor: 8 (Rarely screened, even on first release, available on DVD, hard to find online)